I bought this lens a few months ago and was really excited about the rave reviews of the new IS system on this lens. I originally debated buying this lens vs. the DO version, but to me length of the lens does not matter - though it is annoying when people ask you if you can see the stars with it on. I have to say that the IS does work wonderfully. I do not have a stable hand and I has taking indoor shots with 200mm at f/5.6 and they were turning out clear. If this is why you want the lens then I'd suggest buying it. But I mainly use this lens at the 300mm end and the optics were far from my expectations. I even got shots at f/8 with an almost ghost appearance around my objects (which I tell everyone I did on purpose for an artsy feel). For this reason, I can not recommend buying this lens. I do have to say though, my pics were very crisp and clear at the 70mm end, but as I said earlier, thats not the reason I bought the lens. I will be returning this and trying out the Sigma 100-300 f/4 - faster and has better reviews optically (but sadly no IS).